1. Field
The present application relates generally to wireless communications, and more specifically to techniques for efficiently reestablishing connection between peer-to-peer devices.
2. Background
The 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) represents a major advance in cellular technology and is the next step forward in cellular 3G services as a natural evolution of Global System for Mobile communications (GSM) and Universal Mobile Telecommunications System (UMTS). The LTE physical layer (PHY) is a highly efficient means of conveying both data and control information between an evolved NodeB (eNB) and mobile entities, such as, for example, access terminals (ATs) or user equipment (UE). The LTE PHY employs some advanced technologies that are new to cellular applications. These include Orthogonal Frequency Division Multiplexing (OFDM) and Multiple Input Multiple Output (MIMO) data transmission. In addition, the LTE PHY uses Orthogonal Frequency Division Multiple Access (OFDMA) on the downlink (DL) and Single-Carrier Frequency Division Multiple Access (SC-FDMA) on the uplink (UL). OFDMA allows data to be directed to or from multiple users on a subcarrier-by-subcarrier basis for a specified number of symbol periods.
Examples of older wireless communication systems widely deployed to provide various types of communication content such as voice and data include Code Division Multiple Access (CDMA) systems, including CDMA2000, Wideband CDMA, Global System for Mobile communications (GSM), and Universal Mobile Telecommunication System (UMTS). These wireless communication systems and LTE systems generally use different radio access technologies (RATs) and communication protocols, operate at different frequency bands, provide different quality of service (QoS), and offer different types of services and applications to the system users.
In a direct wireless connection, a first mobile entity transmits a wireless signal directly to a second mobile entity, which receives and processes the wireless signal. Examples of direct wireless connections include connections from a mobile entity to eNB(s) in LTE or other wireless communications protocols, or peer-to-peer (P2P) connections between mobile entities as used in non-cellular protocols such as WiFi Direct or Bluetooth. Cellular wireless communications systems do not typically include direct connections between mobile entities. Rather, the mobile entities typically communicate indirectly with one another through one or more NodeBs and associated network infrastructure. In this context, in response to suspension of a previous P2P session between mobile entities, there is a need for efficiently reestablishing the P2P connection and the previous session state.